1. Field of the Invention
The invention relates to a stent/graft deployment catheter, particularly for repairing defects in arteries and other lumens within the body. More particularly, the invention relates to a reduced diameter stent/graft deployment catheter for delivering a stent/graft in situ for repairing defective body lumens, aneurysms, and particularly abdominal aortic aneurysms.
2. Description of the Prior Art
An abdominal aortic aneurysm (AAA) is a sac caused by an abnormal dilatation of the wall of the aorta as it passes through the abdomen. The aorta is the main artery of the body, supplying blood to all organs and parts of the body except the lungs. It arises from the left ventricle of the heart, passes upward, bends over and passes down through the thorax and through the abdomen, and finally divides into the iliac arteries which supply blood to the pelvis and lower extremities.
The AAA ordinarily occurs in the portion of the aorta below the kidneys. When left untreated, the aneurysm will eventually cause the sac to rupture with ensuing fatal hemorrhaging in a very short time. The repair of abdominal aortic aneurysms has typically required major abdominal surgery in which the diseased and aneurysmal segment of the aorta is bridged with a prosthetic device, such as a synthetic graft.
As with all major surgeries, there are many disadvantages to the above mentioned surgical technique, the foremost of which is the high mortality and morbidity rate associated with surgical intervention of this magnitude. Other disadvantages of conventional surgical repair include the extensive recovery period associated with such surgery; difficulties in suturing the graft to the aorta; the unsuitability of the surgery for many patients, particularly older patients exhibiting comorbid conditions; and the problems associated with performing the surgical procedure on an emergency basis after the aneurysm has already ruptured.
In view of the above mentioned disadvantages of conventional surgical repair techniques, techniques have been developed for repairing AAAs by intraluminally delivering an aortic graft to the aneurysm site through the use of a catheter based delivery system, and securing the graft within the aorta using an expandable stent. Since the first documented clinical application of this technique was reported by Parodi et al. in the Annals of Vascular Surgery, Volume 5, pages 491-499 (1991), the technique has gained more widespread recognition and is being used more commonly. As vascular surgeons have become more experienced with this endovascular technique, however, certain problems have been encountered. One major problem involves the stiffness of the catheter body. Surgeons have encountered difficulty in navigating the prior art catheter through the vessel tree of a patient. Therefore, the need exists for a stent/graft deployment catheter capable of being more easily navigated through the vessel tree of a patient.
Use of the stent/graft deployment catheter eliminates the problem of suturing the graft to the aorta associated with surgical repair techniques. However, use of the catheter still requires a cut-down surgery to locate and expose the blood vessel and thus the patient recovery time is still quite long. Therefore, the need exists for a stent/graft deployment catheter which can be inserted percutaneously into the blood vessel of the patient. A percutaneous procedure would avoid the surgery necessary to locate the blood vessel and thereby decrease patient recovery time significantly. The presence of such a catheter on the market may finally allow for the full transition from the currently used surgical cut-down method of stent/graft insertion to the much preferred percutaneous insertion method. Such a catheter has not appeared on the market yet because of the difficulty inherent in designing a catheter small enough to be inserted percutaneously. The present invention does not disclose such a catheter. Rather the present invention recognizes the ever existing need for smaller catheters and therefore discloses a catheter design which can be used to decrease the diameter of any catheter on the market including eventually a catheter appropriately sized for percutaneous insertion.
Large catheters are also problematic because they require large size insertion holes which are traumatic to the blood vessel and which require surgery to repair. Therefore, the need exists for a smaller size catheter which may be inserted through a reduced diameter insertion hole in the blood vessel.
Another problem with the use of a stent/graft deployment catheter, regardless of whether it is introduced percutaneously or via the surgical cut-down method, is that its presence in the blood vessel during the stent/graft deployment procedure restricts blood flow in the blood vessel. Therefore, the need exists for a stent/graft deployment catheter which minimizes the amount of blood flow restriction during the stent/graft deployment procedure.